On PHPMaster.com there's a new article that looks at running PHP on a specific environment and some of the considerations the author had to make - using PHP on IBM i.
We’ve talked about a lot of weird things so far on PHPMaster (well, at least I think some of them are weird), but this may take the cake. In this series I want to talk to you about PHP – and the IBM I. That’s right, the IBM i, formerly known as System i and before that as the AS/400. Let’s start by dispelling the myth that the i is dinosaur; it’s actually a very wonderful machine, and there are lot of opportunities for brave PHP programmers who venture into this realm.
He starts off with "the truth" about the IBM i and some of the features it brings to the table - total system integration, scalability, etc. He talks some about the current GUI the system uses, functionality RPG provides, and some concepts you'll need to think about before getting into PHP on the IBM I.